Thin films of CeO2 deposited by rf magnetron sputtering on sapphire and silicon substrates have been characterized with variable angle spectroscopie ellipsometry, atomic force microscopy (AFM), transmission electron microscopy and x-ray diffraction. A novel multiple model was used successfully for determination of the optical properties and surface roughness of the CeO2films. AFM analysis showed that the CeO2 films have hillock-shaped facet morphology. It was found that the surface roughness of CeO2 increased with film thickness. For films on sapphire substrates, the surface morphology and the crystalline quality were improved by post-annealing, e.g. flat surfaces were obtained after annealing at 1100 °C.